Proceedings, 2012 International Snow Science Workshop, Anchorage, Alaska
Avalanche analysis and management in the ski resort Rosa Khutor regarding the
2014 Sochi Olympics Games
1*
1
2
4
Authors: Fanny BOURJAILLAT , Philippe BERTHET-RAMBAUD , Stefan MARGRETH , Leonid ANDREEV , Alexander
4
3
BOYKO , Jean-Luc VALLIER
1.
2.
3.
4.
Engineerisk, consulting company, Chambery, France
WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland
Mountain manager, Compagnie des Alpes, Rosa Khutor Ski resort, Russia
Avalanche Service, Rosa Khutor Ski resort, Russia
ABSTRACT: The 2014 winter Olympics games will take place in Russia near Sochi in the Caucasus
Mountains. Several sites have been retained there: both close to the Black Sea coast and in the
mountains near Krasnaya Polyana village. The site interesting to this presentation is “Rosa Khutor”. This
newly developed ski resort both by Russian with the cooperation of the French Compagnie des Alpes will
host the alpine ski, freestyle and slopestyle competitions. About 15 lifts are planned for 2014 (including
gondolas, chairlifts and carpets) to provide the access to 80 km of ski slopes.
Five years ago, there was almost nothing at this place except a National Park; it was totally virgin, a wild
space consisting of large forests interrupted partly by avalanche tracks. Everything has been built from
scratch. Only one ski resort exists there since 1993: Alpika Service with five chairlifts west of Rosa Khutor.
This was the experience core to the development of the new modern ski areas: Rosa Khutor, Gornaya
Karussel and Laura.
Rosa Khutor is a challenging zone with many large and steep slopes. This terrain is near the Black Sea
and receives extreme precipitation that can lead to large and dangerous avalanche cycles. Before the
construction of the ski area, the area was used by heliski operations. No avalanche hazard maps or
documentation about the local avalanche history were available; so that everything had to be done about
avalanche hazard management.
KEYWORDS: Olympics games, avalanche study, avalanche management
1. INTRODUCTION
Institutes such as Roshydromet and the local
engineering company, Engprotection (2010).
The area’s first avalanche studies were in 2008,
and performed independently by private groups
Bolognesi (2008) and Stethem (2008). Additional
investigations were made by Russian research
In 2010, Stefan Margreth from the SLF Davos was
mandated to review the existing studies and to
work out a final proposal for avalanche mitigation
measures in the ski resort of Rosa Khutor.
Engineerisk was asked to collaborate for the
preventive release network and management part.
Since then, more than ten missions have been
organized both in summer and winter with the local
avalanche service team. Several topics and
questions have been investigated.
________________________
* Corresponding author address: Fanny
Bourjaillat, Engineerisk, PA Alpespace, Bât.
Cleanspace, 73800 Ste Hélène du Lac, France; tel:
+33479722200; fax: +33479722272;
web:www.engineerisk.com, email:
fanny.bourjaillat@engineerisk.com
134
Proceedings, 2012 International Snow Science Workshop, Anchorage, Alaska
There were no weather stations before 2006 (12
now). In winter 2006/07 a maximum snow height of
507 cm was recorded and local people said that
this was not an extreme winter. In an extreme
winter snow heights can reach 8 m or more,
Efremov (2011).
2. CONTEXT
2.1 General situation
The ski resort Rosa Khutor is quite large and
consists of several terrain bowls. The elevation
varies between 600 m and 2330 m. It has been
developed from the west to the east (from
Westridge to Ober Khutor). These sites are
exposed to the north. Further development
possibilities exist on the South side, behind Aibga
ridge.
Figure.2: Snow heights in Rosa Khutor, Margreth
(2010)
Long-term snow data are missing so it is difficult to
accurately determine the maximum possible snow
heights and there is no reliable weather forecast
for the region so avalanche forecasting and
management can be difficult.
Figure.1: Rosa Khutor sectors, Margreth (2010)
2.2 Climate
The climate results from the interplay of cold air
from the north with moist, warm air from the Black
Sea. The precipitation sums are huge (exceeds
2500 mm per year) and the top parts of the main
starting zones are north-facing which means on
the leeward side of the mostly moisture-bearing
atmospheric fronts. The result is a snow climate
characterized by heavy snow fall, sustained
precipitation periods and moderate temperatures.
The snow fall limit is often higher than 2000 m
a.s.l. According to local experts a typical
avalanche period starts with rainfall up to 2300 m,
afterwards, during sustained precipitation periods,
the freezing level drops down to the valley floor.
Storm periods with a 24 h snowfall of 1 m occur
nearly every winter. Warm periods and snow fall
on unfrozen ground often cause a strong snow
gliding activity.
Figure.3: Example of possible snow height in the
Rosa Khutor area (Alpika Service, 2300 m asl)
2.3 Phenomenon
Two main avalanche problems can be seen in
Rosa Khutor. First, snow accumulations are
particularly important along the wind exposed
ridgeline at the top of the resort.
135
Proceedings, 2012 International Snow Science Workshop, Anchorage, Alaska
can also damage or destroy remote exploders
(e.g. Gazex®) situated below.
Notably in Rosa Bowl, these upper slopes directly
threaten ski runs below. Depending on
temperature, cold slab or heavy and wet snow
avalanches can initiate almost everywhere and run
into the ski area.
Additionally, in Ober Khutor or East Bowl where
many bowls overhang long steep slopes, huge
avalanches are possible, entraining large snow
volumes able to reach the lower altitudes and
especially the Rosa Lake plateau above the
Olympic races finish zone.
Except for the central part of the Lower Area (Fig.
1) where the freestyle competitions will take place
all of Rosa Khutor is potentially exposed to hazard.
According to the data from the automatic weather
stations, the temperature of the snow pack is
practically isothermal all winter. This fact in
combination with the heavy snow climate promotes
snow gliding. It occurs on slopes steeper than 25°,
particularly when the ground is warm and the
vegetation not very high or conduct to slippery
interface. Glide cracks can appear early in winter
but it is difficult to predict snowglide avalanches as
it can occur anytime. It is considered to be one of
the biggest issues in Rosa Khutor which is very
difficult to manage.
Figure.5: Cornices in Rosa Bowl, L. Andreev
1.2 Ski resort organization
Several patroller teams were formed similar as in
Europe or USA: for rescue, slopes management,
operation of lifts… and one small avalanche
service (some people). The big difference in Rosa
Khutor is that the different teams work mainly
independently. It means that if an avalanche
happens during the day, only the avalanche
service intervenes. In the same way, if it’s
necessary to release avalanches before opening
the ski resort during unstable snow conditions, the
avalanche service normally does that. This
originality leads to some efficiency questions. It’s
planned to unify the different patrollers’ teams.
Concerning avalanche management, the use of
explosives is usually forbidden. This point is very
restrictive. Effectively, lots of little dangerous
slopes, which could be treated by hand charges,
are finally equipped by gas devices: Gazex®,
(Shippers, 2001). More than 50 Gazex® will be in
operation for the season 2012/2013 in Rosa
Khutor and Ober Khutor to protect an area of 5
2
km above 1500 m asl.
Since one year, Rosa Khutor tries to get a licence
to integrate the Avalancheur system (Bolognesi,
2000) in the avalanche control plan and to use
hand charges of liquid explosives. Two shooting
positions have been chosen for the Avalancheur
system. This would be important first to optimize
organization, adapt means and to provide an
alternative in the case of an unusual situation.
Figure.4: Snow gliding in Rosa Bowl
Huge cornices with heights of more than 10 m are
regularly formed in many locations of the ski
resort. The biggest cornices appear along the
Aigba ridge by strong winds coming from the
south-west.
As they often overhang steep slopes, cornices can
collapse and then release large avalanches. They
136
Proceedings, 2012 International Snow Science Workshop, Anchorage, Alaska
and the design of structural protection measures.
The simulations permitted to determine the
reference pressure, snow height, velocity values
then used to design future protections (dam,
pylons sizing…).
Tests were performed with the helicopter-borne
system DaisyBell® (Berthed-Rambaud, 2008) in
2010 but local weather conditions particularly
constrain its use: for instance, helicopter could fly
only one day during March 2011: for that, it can be
just an additional option.
2. RISK & PROTECTIONS STUDY
3.1 Risk assessment
The site has been gradually developed. From
Rosa Bowl where the Olympic race courses are
situated, to Ober Khutor, a fantastic off-piste area,
and possibly Yurev and Yuhsni sectors in the near
future. Before evaluating the adapted mitigation
measures for lifts, stations, ski tracks and other
infrastructure, it was necessary to define the
different avalanche starting zones, to assess the
runout of possible avalanches and to define the
endangered areas.
To determine at best the endangered zones
without many available data, lots of field analysis,
visits and avalanche simulations have been
conducted. A very reliable source of information
was the state of the forest which clearly showed
the frequency of avalanche events. The runout
distances and the avalanche actions were
quantified with the avalanche dynamics software
RAMMS (Christen, 2010). In parallel, the hazard
zones were carefully verified in the field.
Avalanche simulations were performed for all
relevant release areas. The definition of input
parameters was challenging because of missing
experience with RAMMS in the area. Observed
avalanches were back-calculated to verify the
input parameters and to get the most accurate
results as possible. The assumed fracture depths
vary typically between 1.0 m and 2.1m in relation
to the elevation, inclination and frequency.
Effectively the more the slope is steep the less
there will be snow, because avalanches will
release earlier. Whereas when slopes are less
steep or if snow drift accumulations are likely, the
fracture depths are larger.
Hazard maps were prepared for a 10-year and
100-year scenario. The 10-year scenario was
applied mainly for the evaluation of ski tracks and
the 100-scenario for the evaluation of lift, stations
Figure.6: RAMMS simulation to get avalanche
pressure for a return period of 100 years
(Margreth, 2010)
2.2 Protections against avalanche
It was very challenging to reach an acceptable
safety level without the possibility to apply
explosives. After the different release areas and
hazard zones were defined, the optimal protection
strategies had to be defined. About passive
protection, two dams have been designed.
Gazex®
Dam
Figure.7: Deflection dam and avalanche from the
starting zone Westridge 1 ( Margreth, 2010)
137
Proceedings, 2012 International Snow Science Workshop, Anchorage, Alaska
(Fig.9) whereas lots of small slopes could have
been protected with hand charges (easy access,
small surface…)
One deflecting dam was built to protect the
junction between two important lifts. This dam is
10 m high; it has been sized for a return period of
10 years knowing that the threatening zone has to
be released/treated by Gazex®.
A second, catching dam, is situated below East
Bowl. It protects two artificial lakes for snowmaking
(lower eastern part of the ski area) and some ski
slopes as well. This dam is also 10 m high.
For smaller elevations and smaller slopes, where
snow glide has to be expected, snow nets were
proposed. One of the key factors for the planning
was the definition of the extreme snow height. The
snow height is crucial for the effectiveness of the
structures and the design. An overfilled structure
can lead to avalanches and/or be damaged. In
2012 about 1.3 km of snow nets were built. The
structure height of 4.0 m turned out not to be
sufficient. In Winter 2011/12 many of the snow
nets were overfilled with snow. The application of
snow net was considered not to be advisable in
the higher and bigger release areas because of
too high snow depths and economic reasons.
Figure.9: Example of Gazex locations, Bourjaillat
(2011)
Gazex® are preventive release devices remotely
controlled, which use a mixture of propane and
oxygen to induce an explosion above the
snowpack.
There
are
three
sizes
of
Gazex/exploders, according to their capacity to
3
contain a larger or smaller volume of gas: 0.8m ,
3
3
1.5m and 3m . Varied sizing permits the adaption
of the release system to the surface of the starting
zone. Exploders are alimented by pipes linked to
shelters which stock gas bottles.
Snownets barely
perceptible
Figure.8: Covered snownets in the middle of
Eastbowl
That’s why the artificial release of avalanches was
chosen for the protection of most of the starting
zones. In the first years, fixed installed Gazex®
exploders were the only authorized system
available in Russia but now the use of an
Avalancheur seems possible in the near future.
Most starting zones, small and big ones, have
been protected with Gazex®. It led to a really big
quantity of them in relation to the surface area
3
Figure.10: Gazex® 3m in Rosa Khutor
When installed, Avalancheurs will treat about half
of the possible starting zones in Ober Khutor,
especially at mid elevation where it is not
138
Proceedings, 2012 International Snow Science Workshop, Anchorage, Alaska
recommendable to build fixed installed systems
whereas slopes remain very steep.
The Avalancheur is a civil pneumatic launcher. It
launches an arrow containing 2.2 kgs of
explosives. It can reach several shot points from a
single place thanks to a rotary turret.
An Avalancheur constitutes an all-weather
alternative in case of problem in an already
equipped avalanche path. It provides an efficient
release solution for secondary slopes.
Figure.12: Jet roofs effects in Alpika service, L.
Andreev
However, In Rosa Khutor local management didn’t
decide to prevent cornices formation but to
manage them after or during thanks to a particular
and above all, unique way: excavators.
Figure.11: Avalancheur calculations (BerthetRambaud, 2012)
Russians also developed a short-range manual
gun to release avalanches. This gun contains 200g
of explosives and is able to reach a distance of
200m. It’s currently in development phase.
Many starting zones are situated on or close to ski
tracks. In these areas, it is planned to reduce the
avalanche risk by compaction of new snow with
grooming machines from the beginning of winter
(as soon as it’s snowing).
The avalanche service will also treat the little and
accessible slopes by ski-cutting.
Figure.13: Excavators on Aibga ridge (Margreth,
2010)
2.3 Other phenomena
Two excavators spent all the winter on site to
remove cornices. If the ridge is quite accessible
and smooth to drive on, it remains that this
technique needs time, coordination with grooming
or track opening and is not so environmentallyfriendly. Secondly, cornices can be treated only
after storms and with sufficient visibility - on the
other side the application of the excavator proved
to be quite effective.
Specific snow glide measures were not yet
implemented but it’s proposed to position wood
sleeves perpendicularly to the slope to retain the
first layer of snowpack and limit its glide.
To cope with cornices, snowdrift fences or jet roofs
would be an efficient solution. It allows modifying
the snow transport and displacing accumulation
outside of starting zones. Jet roofs have also been
installed in Alpika Service and show really good
effects. Cornices were interrupted just behind the
jet roofs.
139
Proceedings, 2012 International Snow Science Workshop, Anchorage, Alaska
primarily different parallel and independent
services: this is helping everybody to work
together.
An avalanche atlas has been developed to support
the PIDA. This atlas is a complement to the
general map. It represents each path thanks to
pictures, indicating in which zone it is, how it’s
managed…
3. AVALANCHE RELEASE MANAGEMENT:
PIDA
An avalanche service has been specially created
in Rosa Khutor and is assisted by European
consultant. The ski resort is young and experience
is short. Obviously it needs to spend many years in
one site to know well its specificities; where the
starting zones are exactly, where are snow
accumulations, where is the perfect shooting
point… At the same time, standards to reach are
high, the 2014 Winter Olympic Games are coming!
The avalanche service was really involved to
understand best how to manage avalanches and
try to compensate this lack of time.
To help them, a PIDA (French term for avalanche
control plan), Bourjaillat (2012), was used by the
Russian team during the last winter. This
document is being introduced both technically to
correspond to the local avalanche context and
organization and legally to fit the Russian law
requirements (including the need to get a license
to deal with weather station and avalanches
triggering).
A PIDA is an operational document, compulsory in
France, which consists of a map of the ski resort
with all avalanche zones, shooting points, closed
zones during operation and an “intervention plan”.
In this plan, the organogram of the organization is
specified. This document lists the different tasks
during the release operations and defines the
specific instructions for use of the different
devices.
It is a guideline to assist operations to work as
safely and efficiently as possible.
The first main point was to make the avalanche
service aware of the avalanche problem, its
features and its dangerousness. Especially that
they will have to use Gazex®. To optimize the use
of remote controls systems, it’s crucial to release
avalanches as soon as conditions need it. It was
important for the service to understand that the
purpose is not to wait/undergo but to act quickly,
logically and as safely as possible.
The problem is still due to the lack of accurate
snow forecast: will it be snowing? When? How
much?
The “Russian” PIDA should also be adapted to
their mode of operation, knowing that they were
Figure.14: Example of the Avalanche Atlas,
(Bourjaillat, 2012)
4. CONCLUSION
There were lots of issues there:
We had to compensate for a lack of data and local
experience by using as much as possible the
current and available tools at disposal and field
opportunities knowing that the deadline was quite
short.
We had to quickly understand Russian context and
adapt all protection strategies according to local
snow conditions, internal organization concerns
and regulations...
We had to secure an entire ski resort without using
any explosives. This was obviously a challenge;
especially when 4m snownets at middle elevations
get buried during an average winter.
140
Proceedings, 2012 International Snow Science Workshop, Anchorage, Alaska
REFERENCES
Berthet-Rambaud P., Noel L., Farizy B., Neuville
J.M., Constant S., Roux P.,
, 2008,
“Development of a helicopter-borne gas
device for avalanche preventive release”,
Proceedings of the International Snow
Science Workshop, Whistler 2008, 5p.
Berthet-Rambaud P., 2012, “Artificial release
network”, 29p
Bolognesi
R.,
Meffre
J.F.,
2000,
“L’AVALANCHEUR Lacroix type 1732”, Les
cahiers techniques METEORISK n°1, 34p
Bolognesi R., 2008, “Avalanches à Rosa Khutor:
étude des risques et des possibilités de
protections Site olympique de Sochi
(Russie)”, 41p.
Bourjaillat F., 2012, “лавина план контроля”, 16p.
Bourjaillat F., Berthet-Rambaud P., 2011,
“Récapitulatif 2011 de la répartition des
Gazex®”, 7p.
Christen M., Kowalski J., Bartelt P., 2010,
“RAMMS: Numerical simulation of dense
snow avalanches in three-dimensional
terrain”,
Cold
Regions
Science
and
Technology 63, p1-14
Efremov V., 2011, “Снежный покров, в бассейне
р. Мзымта“, Proceedings of IV Internbational
conference, avalanche and related subjects
Engprotection, 2010. Report on Avalanche
Defence at Rosa Khutor (in Russian)
Margreth S., 2010, “Proposition of avalanche
defence measures for the ski resort Rosa
Khutor, Ski resort development company
« Rosa Khutor ». SLF Expert report. Davos,
76p.
Shippers J., 2001, “GAZ-EX: 12 années
d’expérience”, Neige et Avalanche n°94, p 911
Stethem C. & Associates Ltd., 2008, “Preliminary
Snow Safety Plan”, 64p.
141